The present invention is particularly directed to a relay of the type in which electrically conductive leads are adapted to be directly attached to the movable contact support member of the relay. Typically, they are attached by trimming off a portion of the insulating cover from the end of the lead, and then soldering or otherwise connecting the exposed wires to the spring arm or to another conductive portion of the armature assembly.
This is not a very satisfactory manner of construction. Specifically, as the armature assembly pivots back and forth during the operation of the relay, the exposed wires will be caused to bend first in one direction and then the other; and although the extent of bending might be quite small, it will gradually weaken the wires until eventually they are likely to break. This can result in a costly period of downtime for the equipment being operated by the relay, as well as in the need to repair or replace the relay.
Recognizing the high potential for wire breakage, workers in the art have endeavored to design relays that are better able to withstand the bending forces imparted to the lead by the pivoting movement of the armature. One approach has been to additionally attach the lead to the movable contact member at a second position farther back along the lead so that the bending forces will be shifted back from the vicinity of the exposed wires to a location where the insulating cover of the lead is still intact such that the lead will be much better able to withstand the forces. Typically, this is done by attaching some sort of clamping element to the movable contact member and then clamping the conductive leads in place.
There are several disadvantages to this approach. Initially, it increases the complexity and hence the cost of manufacturing the relay. In particular, relays in which conductive leads are connected directly to the movable contact member are typically of the type which are incorporated into several different switching circuits to simultaneously switch several different loads. Accordingly, they include several sets of contacts; and it is necessary to attach a conductive lead to the movable contact member of each set. This means that a plurality of clamping elements are required, and each must be attached to a movable contact member and a lead secured in each clamp. Also, since the clamping elements are frequently made of metal, care must be taken to ensure that the several movable contact members are kept electrically isolated from one another to the proper extent; and this sometimes necessitates an increase in the overall size of the relay which is undesirable as such relays are frequently mounted on printed circuit boards where size is an important factor.